Effects of environmental conditions associated to the cardinal orientation on the reproductive phenology of the cerrado savanna tree Xylopia aromatica (Annonaceae)

Maria Gabriela G Camargo,Regina M Souza,Paula Reys,Leonor P.C Morellato

doi:10.1590/s0001-37652011005000014

Maria Gabriela G Camargo, Regina M Souza + Show 2 more

Open Access

https://doi.org/10.1590/s0001-37652011005000014

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Abstract

The Brazilian cerrado has undergone an intense process of fragmentation, which leads to an increase in the number of remnants exposed to edge effects and associated changes on environmental conditions that may affect the phenology of plants. This study aimed to verify whether the reproductive phenology of Xylopia aromatica (Lam.) Mart. (Annonaceae) differs under different light conditions in a cerrado sensu stricto (a woody savanna) of southeastern Brazil. We compared the reproductive phenology of X. aromatica trees distributed on east and south cardinal faces of the cerrado during monthly observations, from January 2005 to December 2008. The east face had a higher light incidence, higher temperatures and canopy openness in relation to south face. X. aromatica showed seasonal reproduction at both faces of the cerrado, but the percentage of individuals, the synchrony and duration of phenophases were higher at the east face. The study demonstrated the influence of the environmental conditions associated to the cardinal orientation of the cerrado faces on the phenological pattern of X. aromatica. Similar responses may be observed for other species, ultimately affecting patterns of floral visitation and fruit production, which reinforces the importance of considering the cardinal direction in studies of edge effects and fragmentation.

Highlights

The process of fragmentation of plant communities increases the proportion of edges, leading to changes in the microclimate such as increasing temperature and luminosity, and the impact of winds and decreasing humidity in the marginal portions of the fragment, called edge effects (Murcia 1995, Kapos et al 1997)
Significant differences between the percentage of individuals reproducing at the east and south faces were observed for all phenophases in 2006, flower buds and anthesis in 2007, and flower buds and immature fruits in 2008, with higher medians at the east face (Table I)
The seasonal climate is regarded as the main factor defining the phenology patterns of cerrado savanna vegetation, leading to the recurrent reproductive seasonality found for many species of cerrado (Felfili et al 1999, Batalha and Mantovani 2000, Oliveira and Gibbs 2000, Lenza and Klink 2006) which is considered an adaptive strategy of cerrado plants (Oliveira and Gibbs 2000, Oliveira 2008)

Summary

Introduction

The process of fragmentation of plant communities increases the proportion of edges, leading to changes in the microclimate such as increasing temperature and luminosity, and the impact of winds and decreasing humidity in the marginal portions of the fragment, called edge effects (Murcia 1995, Kapos et al 1997). The cerrado savanna has undergone a drastic reduction, remaining about 34% of its original extension (Klink and Machado 2005, Silva et al 2006). Climate at local and micro scales is the key driver shaping the time of plant reproduction, flowering, with consequences for the ecosystem, since it affects all chains of plants and animals interaction (Marquis 1988, Fitter and Fitter 2002, Goulart et al 2005). Duration and synchrony are among the key parameters used to describe plant phenology and its relation to climate or evolutionary factors (Augspurger 1983, Herrera 1988, Newstrom et al 1994, Bolmgren 1998)

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